Feed mechanism



Oct. 20, 1931. J. F. WILLIAMS ET AL 1,828,552

' FEED MECHANISM Filed April 17, 1929 I 2 Sheets-Sheet 1 140 L i &4

90 f x I I 75 92 ,76 53 4 3 2' ar ILE 50 98 I I I H 2'8 95 Fig. 2

Fig: 3.

1929 2 Sheets-Sheet 2 Oct, 20, 1931. J. F, WILLIAMS ET AL FEED MECHANISM Filed April 17 u some parts in section.

Patented Get. 20, 1931 UNITED ISTAT S' PATENT oF-F c-E a JAMES F. WILLIAMS, on LYNnHURsT, AND RAYMOND H. cit-AMER. on NEWARK, vnw JERSEY, ASSIGNORS T0 GENER-AL'MoToRs ooarona'rron; 0F DETROIT,.MICHIGAN,

A'conronarlon or DELAWABE" FEED MECHANISM Application filed April 17,

5 ject of the invention is to provide improved feed mechanism whereby bothcoarse and fine feeds may be obtained in sequence. Another object is to-provicle improved mechanism for reversing the feed, especially of a grinding wheel or a work head, in order to prevent marking the work atthe conclusion of grinding and to position the wheel and the work for anew grinding operation. Another object is to provide improved back off mechanism for facilitating the repetition of a out without damage to the work and with minimum attention by the operator. Another object is to provide improved feed mechanism which accurately compensates for wear, of a cutting tool. To these ends and to improve generally and in detail upon devices of this general character, the invention further consists in the various matters hereinafter described and claimed.

In its broader aspects the invention isnot necessarily limited to the specificembodiment selected for illustrative purposes in the accompanying drawings in which Fig. 1 is a front view of the device with Fig. 2 is a planview.

Fig. 3 is aside View with some parts in vertical section and some broken away. I

Fig. 4iis a front view of one form of cutting machine to which the invention is applicable.

Fig. 5 is a front View of a modified construction. v

Fig. 6 is a front view of certain; details thereof.

Fig. 7 is a side view of parts shownv in Fig. 5.

Fig. 8 is a perspective View of a detail.

The. invention is especially applicable to cutting machines such as internal grinding machines having a longitudinally reciprocating table 6carrying a cross feed slide 8 for the grinding wheel 10. Any suitable work head may be mounted on the bride 11. The numera1 12 indicates a screw stud for fastening to the cross slide 8 and having asplit nut 14 1929. Serial No. 355,848.

engaging the threads 16 of a feed shaft/ 18 V whichcan be turned,.either by a, hand wheel 20, whose hub 22 is keyed to the shaft and held by a nut 24, or by pawl andratchet mechanism. An actuating arm havinga hub 26 is rockably mounted on the 'hub 22 and on an extension 28 of a ratchet-wheel 30keyed to the shaft. A bushing 32 is held on the shaft by a sleeve 34 which is secured to the shaft by a taper pin 36. Rotatable on the bushing is a sleeve 38 having a flange 40 entering a recess in wheel 30 and secured by screws to a flange 42 on a ratchet whee1'44. Thelsleeve 38 is exteriorly threaded, in a direction opposite tothat of the screw. threads 16 and engages cooperating threads on a nut 46 seated in an annular projection 48 of a bracket 50 which is attachable to the longitudinally reciprocating tableto slide therewith. The

nut is secured to the bracket by screws 52 passing through a flange 54 and the threads are lubricated from an oil cup 56 leading to registering ducts 58 in bracket. and nut.

These threads may have the same pitch asthe threads 16 or may be coarser.

A spiral spring 60 is fastened at one end by a screw tothe outside of theprojection 48 and is fastenedat the other end by a headed pin 64 to the ratchet wheel 44 whoserim overlaps a circular face 66 of the bracket 50 to form a housing. Accessto the screw is provided by an opening 168 having a detachable cover plate 70. The spring is wound up by ratchet mechanism duringthe feeding and is entirely housed with provision for some.

and its nut 38 will cause bodily movement of the feed shaft axially and soadvance the nut 14 and its cross slide bodily. When the ratchet wheel 30 is turned too, there isan additional movement of the nut 14 and cross slide because of the feed shaft threads 16 rotating in the nut. Both actions occur initially for a coarse feed and later onlygone for a fine feed. A ring 7 2, set in a recess of the ratchet wheel30, carries a pluralityof springfingers 7 4 bearing against the flange 42 to hold the,

wheels 30 and 44 together frictionally for simultaneous rotation while allowing subsequent rotation of one wheel independently. lVheel 30 carries a felt dust ring 76 engaging wheel 44.

The rim of wheel 44 is provided with two series of teeth 78 and 80 divided by a groove 82 in which a ring 84 can be rotatably adj usted and held by a set screw 86 (Fig. 1). The ring may be split at one point and the sections joined by a plate 88 having fastening screws 90. A lateral projection or shield 92 extends over the series of teeth 78 and has inclined ends or cams 94 to lift a pair of pawls as will appear. The ratchet wheel 30 has a bevelled surface 96 which may be provided with a scale numbered in accordance with teeth 98 on its periphery. There are two pawls 100 for each series of teeth 98 and 7 8, one pawl of each pair being set half a tooth ahead of the other so that coarser teeth may be employed for a better grip without increasing the minimum possible feed stroke of the ratchet wheel.. Twin pawls are not essential however. The pawls are secured to pawl levers 102 spaced apart by washers 104 and pivoted on a shouldered stud 106. which is secured by a nut 108 to a swinging arm 110 carried by the hub 26. The pawl levers have short arms 112 arranged to engage adjustable lifting screws 114 (one for each pair of pawl levers) threaded in an arm 116 projecting'from the bracket 50. An adjusting stop screw 117 is also threaded in arm 116 to engage the swinging arm 110 to limit the downward movement of the arm and so adjust the beginning and amplitude of its stroke. Astud 118 is secured by a nut 120 to the end of the swinging arm 110 and projects rearwardly past the hubs of the pawl levers. Leaf springs 122,

one for each pawl, press the pawls towards the ratchet wheels and are all secured to the stud 118 by a clamp plate 124. The end of the stud 118 carries a shouldered screw 126 with a bushing 128 .rotatably supporting a cam roller 130 which intermittently engages a cam 132 on a cam plate 134 adjustably fastened by a set screw 135 to a rock rod 136. The roller rides up the cam and swings the arm 118 when the reciprocating table, which carries the feed mechanisms, moves to the left in Fig. 1. When the roller rides down the cam, each pawl arm 112 may engage its screw 114 and be lifted from the ratchet wheel, while the swinging arm 110 is arrested by its screw 117. The stroke of the arm 110 is ad j'usted by the screw 117 and the beginning of the stroke of the two pairs of pawls can be varied by independent adjustment of their screws 114. In other words, the screws 114' can be set so that they will let the respective pairs of pawls swing towards .the ratchet wheels at different times to skip more or less ratchet teeth as the swinging arm is lifted by the cam.

The rock rod 136 is journalled in lugs 138 on the bracket 50 and is pinned at one end to a collar 140 having a stud 142 connected by a coil spring 144 to a stud 146 on a housing 148 secured by screws 150 to the frame of the machine, a locating tongue 152 on the housing entering a slot in the frame. The spring normally holds the cam 132in the path of the roller 130 but the cam plate can be rocked forwardly to get it out of the path of the roller when it is desired to stop feeding as when the work reaches size. The collar 140 is pinned to a shaft 154 j ournalled in the housing 148 and having a squared portion carrying an arm 156 with a core pin 158 entering the core of a solenoid 160. The solenoid may be energized in any suitable way asby the control of a feeler gauge which rides on the work. Thus the solenoid will attract the core pin and rock the shaft to move the cam out of the path of the roller. The same rocking movement of the shaft is made to initiate a reverse feed or back off device operated by the spiral spring 60.

As the ratchet wheel 44 is turned by the" pawls, the spiral spring 60 becomes tensioned but the ratchet wheel is locked against reverse movement by a pair of pawls 162 (like pawls 100) engaging the set of teeth 80. The

pawls are carried by latch levers 164 pivoted at 165 to the bracket '50 and pressed to locking position by coil springs 166 set in recesses of a lug 167. An adjusting screw 168 engages both levers while carried by one end of W a trip lever 170, pivoted at 171 on the bracket 50 and having an adjusting screw 172 engaging a rock arm 174 operating through a notch 176 in the bracket 50 and secured by a key 178 to the rock shaft 136 between lugs 138. The rock shaft has a long keyway 179 so that the arm can berocked by the shaft in different longitudinal positions of the brack et 50 with which the arm shifts longitudinally of the main frame. Thus, when the shaft is rocked at the conclusion of grinding,

the pawls 162 are tripped and thecoil spring turns the wheel 44 backwardly until a stop plate 180 on the rim of wheel 44 engages a plunger 182 backed up by a resilient bumper 184 in a bore of a boss 186. This back 011' does not occur of course until after the shield 92 lifts the rear pair of feed pawls 100 and until after the ratchet wheel 30 has had its turning movement independently of the o 7 ratchet wheel 44. WVhen the rear pawls 100 areraised, the wheel 44 stops turning but the wheel 30 can thereafterturn alone because the sprlngs 74 allow shp and are not strong enough to transfer any further turning movethe reciprocating table or carrier by bolts 192 *and'itssides having. inclined ways, 194 which ,form extensions of the ways out in the table for thecross slide. a

In operation, reciprocation of the cross feed mechanismwith the table causes the cam roller 130'to engage the cam-132 thereby actuating the pawls 100, the rear pair of pawls, which are preferably set for a coarse feed, turning the ratchet wheel 44 and causing an axial bodily shifting of the feed shaftand nut 14.; The ratchet wheel 30.i's simulta neously turned at the same speed because the spring fingers 74 hold the ratchet wheels together and'thus the screw threads 16 advance the nut 14-to a further extent. When the previously set' shield 92 reachesttherear pair of pawls and lifts them from, the ratchet, the ratchet wheel 44 stops feeding with the spiral p g 60 under tension, but the front pair of pawls,-which are set for a fine feed, advance the ratchet wheel 30 slowly and cause a slow advance of the nut 14 bythe' screw threads 16,. the axial shifting of the feed shaft 16 having ceased. When. thefinished size of the work is reached, as determined by .any suitable feeler gauge which controlsv an electric circuit, the solenoid 160 is energized to rock the shaft 136. The cam 132 is moved 7 out of the path of the roller130 to stop the fine feed and the locking pawls 162 are tripped. The ratchet wheel 44 is turned backwardlyto its original position by the spiral spring, the stop plate 180 andplunger 182 yieldingly stopping the wheel. The ratchet wheel 30 is likewise turned backwardly because of, the spring fingers 74 holding the two wheels together. Thusthe feed shaft 18 is moved back bodily endwise to its, original longitudinal position while the screw threads 16 are turned back to bring the nut 14 back towards but not quite to the original posiiion,.thc difference from the original posiand the grinding always ceases and-back off occurs at this instant .under controlof thegauge. The amount of back off depends on the settingof the shield 92 and is determined by the quantity of stock to be removed plus some additional amount for safety so that the grinding wheel will clear a subsequent unground work-piece. A subsequentcoarse feed advance of the nut 14 bythe. simuli'nechanism.

housing. the solenoid attracts the core to rock the shaft 210 and operate the trip lever arm 200 and also initiates returnmovement when the soletaneous'rotationo'f thetwo ratchet wheels .must be precisely equal to the amountof back, off but additional wear occurs meanwhile on the; grinding wheel so that the cutting edge does notadvance quite sofar as The nut. Hence, the subsequent slow speed advanceof'the nut by theindependent rotation of the one ratchet wheel 30 takes care of the remalning stock to be reinoved and makes up for wear on the grinding wheel, and

any reduction in size due to dressing, the

gauge;again stopping the grinding wheel when its cutting edge is at the same point as before.

. F igsf5, 6, 7 and 8 illustrate a modifioationi of the trip mechanism whichenables a shorter rock shaft to. be used and otherwise simplifies the mechanism. The lever 17 0 having the headed screw 168 which tripsthe pawl levers 164 has a long arm 200 offset forwardly 'a little and carrying a pin 2 02 arrangedunder a movable cam plate 204 which is elongated in the direction of the-length of the arm. The cam plate has a cupped enof a rock shaft 210. .Spaced ears 212 and 214 on the plate form a slot to receive a nut 216 threaded on a stud 218 adjustable vertically in aligned bores-of the ears. A cam 220 at the upper end of the stud is arranged [0 operate the roller 130 of. the ratchet feed mechanism and is adjustable vertically by the nut to vary the throw of the roller. The lower end of the stud 218 is reduced in size and slotted as at 222 to: receive a pin 22411 which preventsrotation of the stud. The

cam 220 is inclined downwardly towards the roller and is alsoconvexly rounded alittle on the top. The cam plate 204 also has an inclined face 226 at the end towards the-pin 202 soihat ifthe cam plate is depressed [when the pin is beyondit, the pin will be cammed downwardlyon the next inward stroke of the table carrying. the cross feed The rock shaft 210 is journalled in lugs 228 of a bracket 230 which is fastened by clamping bolts 231 on the machine frame, collars. 232 secured to theshaft engaging the lugs for preventing. axialmovement ofthe shaft. A forked arm 234 is keyed to the -shaft and pivotally connectedby a'rod 236 tov a forkedarm238 pinned on a Sllitflj1240 which is-journalled intamhousing 242 which encloses a solenoid". Pinned to the shaft,in-

side the housing is a bent arm 24.4.haying a core 246 toenter the windings of a solenoid 248 which is pressed against therear wall of the housing byleaf springs'250r A spring pressed headed plunger .252 is carried in the core in positionto engageasurface 254 on the The plunger acts as a buffer when largement 206 secured by a pin 208 to the end 1 9 noid is' "dc-energized. An adjustable stop screw 256 is threaded in the housing cover to engage thebent arm 2% and so locate the cam plate 204' in proper relation to the roller 75 l and trip lever arm 200.

1. In a cross feeding mechanism, ashaft having threads, ashiftable' nut engaging the threads, a threaded sleeve rotatably -journalledon the shaft, a bracket, anut fixed to the bracket and threaded on the sleeve, means for simultaneously turning therotary sleeve and the shaft to produce a coarse feed of the shiftable nut, and means for turning the shaft independently of the rotary sleeve for producing a fine feed of the shiftablenut; substantially as described.

2. In a cross feeding mechanism, a shaft having threads, a shiftable nut engaging the threads, a threaded sleeve rotatably journalled on the'shaft and held from axial move- 'ment with respect to the shaft, a bracket, a nut fixed to the bracket and threaded on the sleeve, means for turning the sleeve to produce bodily shifting of the shaft and its nut, means for stopping the turning -m'ovement, and means for thereafter turning the shaft at slow speed to produce a fine feed of the shiftable nut; substantially as described.

3. In a cross feeding mechanism, ashaft havingthreads, a'shiftable nut engaging the threads, a threaded sleeve rotatably journalled'on the shaft, a bracket, a nut fixed to the bracket and threadedon the rotary sleeve, ratchet mechanism for simultaneously turning the sleeve and-the shaft to produce a coarse feed ofthe movable nut, ratchet mechanism for turning the shaft independently of i the sleeve to produce a fine feed of the movable nut, and a spring, tensioned during feed,"for producing reverse movement of the "sleeve and shaft 2 substantially asdescribed.

4. In a cross feeding mechanism, a shaft thebracket and th'readed'on the sleeve, means 5. In across feeding mechanism, a shaft, a

threaded sleeve "rot'at'ably journalled on the shaft," a bracket, a nut fixed to'the bracket and threaded on the sleeve, means for turn.- ing the rotary sleeve to cause a. bodily shifting of the shaft, and a spring having connections 'With the bracket and the rotary sleeve for 7 reversin the sleeve and retracting the shaft;

"substantially as described.

*6. Ina cross feeding mechanism, a shaft, a threaded sleeve rotatably 'journalled in the shaft'and l'ield' against axial movement with "respect to the shaft, "a bracket-,'a--nut fixed to the bracket and threaded on the sleeve, a

ratchet wheel connected to the sleeve,-a spring connected to the Wheel and to the bracket,

means for turning the Wheel and sleeve'to tension the spring and shift the shaft, a pawl for locking-the Wheel with. the spring under -tension,and tripping mechanism for the'pawl to allow the spring to reverse the Wheel and sleeveto'retract the shaft; substantially as described.

7. 111 a cross feeding mechanism, a shaft having threads, a shiftable'nut engaging the threads, a threaded sleeve rotatably journalled on the shaft, abracket, a nut fixed to the bracket and'threadedon thesleeve, a

ratchet Wheel'ca-rried by the sleeve, aratchet Wheel carried by the shaft, a spring between the wheels, a coarse feed pawl for'turning both Wheels together, a-fine feedpawl for actuating the shaft, a reciprocating carrier for the shaftand the arm, a rock shaft having a cam in the path of the arm to cause actuation of the arm When the carrier reciprocates, and means for rocking the rock shaft to move the cam out of the path of the arm to stop the arm actuation; substantially as described.

'9. In a cross feeding mechanism, a feed shaft, means comprising a movable arm for actuating thefeed shaft in one direction for feeding a reciprocating carrier for the shaft and the arm, mechanism for reversing the movement of the feed shaft, a rockshaft having a cam in the path of the arm to cause actuation of'the arm when the carrier reciprocates, and means for rockingthe'rock shaft to move the cam out of the path'of the arm for stopping the feed and rendering the reversing mechanism effective; substantially as described.

10. In a cross feeding mechanism, a feed shaft, means for actuating the feed shaft in one direction for feeding, mechanism for reversing the movement of the feed shaft,

locking means for the reversing 'mechanism,"

a rock shaft, electrically operated means for rocking the shaft, and means carried by the rock shaftfor effecting a stopping of the "feed and a release of the locking means for rendering the reversing mechanism effective;

substantially as described.

11. In a cross feeding mechanism, a feed shaft, means for actuating the feed shaft in one direction for feeding, mechanism for reversing the movement of'the feed shaft, a

latch for locking the reversing mechanism, a tripping lever for the'latch, a reciprocating carrierfor said parts, a frame supporting said carrier, a' rock shaft rockably'mounted *on'the frame, and an elongated plate carried 13. In a cross feeding mechanism, a meinber to be fed, a plurality of feeding devices operable simultaneously for imparting a coarse feed to the member, means for subse quently operating one of the feeding devices independently of the other to impart a fine feed to the member, and means for causing simultaneous reverse movement of both feeding devices to the extent of their coarse feed advance; substantially as described.

14. In a compensating cross feeding mechanism, a tool having a cutting surface to be for rotating both ratchet wheels simultaneously, means for rotating one of said ratchet wheels independently of the other, a feed shaft connected toone of said ratchet wheels and having driving connection with the member to be fed, and means for causing said rotation of said other ratchet wheel to effect an axial movement, thereof with the shaft; substantially as described.

In testimony whereof we hereunto aflix our signatures.

JAMES F. WILLIAMS. RAYMOND H. CRAMER.

fed repeatedly to a definite point to reduce a plurality of work-pieces successively to the same size, a plurality of feeding devices operable simultaneously for imparting a coarse feed advance to the tool, means for subsequently operating one of the feeding devices independently of the other to impart a Wear compensating feed to the tool sufficient to bring its worn cutting surface to said definite point, and means for causing simultaneous reverse movement of both feeding devices to the extent of the coarse feed ad- Vance; substantially as described.

15. In across feeding mechanism a feed shaft, means comprising a movable arm for actuating the feed shaft'in one direction for feeding, a reciprocating carrier for the shaft and the arm, mechanism for reversing the movement of the feed shaft, locking means for the reversing mechanism, a rock shaft having a cam in the path of the movable arm to cause actuation of the arm when the carrier reciprocates, means for rocking the rock shaft to move the cam out of the path of the arm for stopping the feed, and mechanism actuated by the rock shaft for releasing said locking means and thereby rendering the reversing mechanism effective; substantially as described. p

16. In a cross feeding mechanism, a member to be fed, apair of ratchet Wheels operable simultaneously for imparting a coarse feed to the member, means for subsequently operating one of the ratchet wheels independently of the other to impart a fine feed to the member, and mechanism for automatically causing a definite reverse rotation of at least one of the ratchet wheels to retract the member; substantially as described.

17. In a cross feeding mechanism, a member to be fed, a pair of ratchet wheels, means 

